• Proceedings of the KIEE Conference
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• 1999.11d
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• pp.953-955
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• 1999

The (1-x)$MgTiO_3-SrTiO_3$ (x=0. 0.1, 0.2, 0.3) ceramics were prepared by the conventional mixed oxide method. The structural properties were investigated with sintering temperature and composition ratio by XRD, SEM and BT-TGA. Increasing the sintering temperature from $1300^{\circ}C$ to $1600^{\circ}C$, second phase was decreased and grain size was increased. The average gram size of the 0.8$MgTiO_3-SrTiO_3$ ceramics sintered at $1600^{\circ}C$ were $3.61{\mu}m$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.04b
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• pp.91-91
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• 2009

In the past decade, Pd based thin films have been studied far hydrogen gas sensors due to their high possibility for energy industry and environmental applications. In this work, we report a navel method to fabricate highly sensitive hydrogen gas sensors based on PdO thin films. The films were deposited on Si substrates in Ar and $O_2$ ambient using reactive sputtering system. A semiconductor process has been utilized to fabricate PdO films with t=40nm. We observed the resistance changes of the PdO films with various $H_2$ concentrations. It was found that the electrical properties of the thin films depend on the composition of oxygen. The sensitivity is defined as $S\;=\;(R_0-R)/R{\times}100%$, where R and $R_0$ are the resistances in the presence of exposing the hydrogen gas and air, respectively. The sensitivity of the thin films was found to be as high as about 95%. After exposing to hydrogen gas, we discovered that the nano-sized cracks formed on the surface of the PdO thin films. The nano-cracks formed in deoxidized PdO thin films were known by playing a key role to reduce more than 4 times the response time of absorption. Our results illustrate that the deoxidized PdO thin films can be used as hydrogen sensors.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.607-610
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• 2004

The Pb $(Zr_{0.52}Ti_{0.48})O_3/(Ba_{0.6}Sr_{0.4}TiO_3$ [PZT(52/48)/BST(60/40)] heterolayered thin films were fabricated on the Pt/Ti/$SiO_2$/Si by RF sputtering method. The structural properties of the PZT(52/48)/BST(60/40) heterolayered thin films were investigated with Ar/$O_2$ ratio condition. All the PZT(52/48)/BST(60/40) heterolayered thin films had shown the PZT(111), (200) and BST(200) Peaks of the tetragonal structure. Increasing the Ar/$O_2$ ratio, the average roughness was increased. The thickness ratio of the to the PZT and BST thin film was 1:2. In the case of the PZT(52/48)/BST(60/40) heterolayered thin films with Ar/$O_2$ ratio of 80/20, the average roughness was 3.4 [nm].

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.365-366
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• 2005

PZT films are the most intensively investigated because PZT has advantages such as low processing temperature and large remnant values. In this paper, the microstructure and electric properties of $Pb(Zr_x,Ti_{(1-x)})O_3/BaTiO_3$ heterolayered thick films with Zr mole ranging from 30 to 70 % screen printed onto a alumina substrate were studied. $Pb(Zr_x,Ti_{(1-x)})O_3$ and $BaTiO_3$ powders were prepared by the sol-gel method. The $BaTiO_3$ powders were calcined at $700^{\circ}C$ for 2 hours. Structural properties of $Pb(Zr_x,Ti_{(1-x)})O_3/BaTiO_3$ multilayered thick films were investigated. As a result of the X-ray diffraction (XRD) analysis, $Pb(Zr_x,Ti_{(1-x)})O_3/BaTiO_3$ exhibited a perovskite polycrystalline phase without pyrochlore phase or any preferred orientation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.412-415
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• 2004

PTC Thermistors specimens were fabricated by added $MnO_2$ as donors, and $Nb_2O_5$ as accepters and sintered $1250^{\circ}C/2hrs$. Average grain size decreased with increased in added $MnO_2$, and increased with added in $Nb_2O_5$. But, appeared liquid phase as $BaTiO_3$ and $TiO_2$, affect to grain growth. XRD result, peak strength waslowed then crystallization not well, but, secondary phase were not showed all specimens. All specimens resistance were so high, about $40M{\Omega}$ over, couldn't measured to those resistance and doesn't appear PTCR effect.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05c
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• pp.127-130
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• 2001

The $BaTiO_3+xNb_2O_5$(x=6, 8, 10wt%) ceramics were prepared by conventional mixed oxide method. The structural properties of the $BaTiO_3+Nb_2O_5$ ceramics with the sintering temperature and addition of $Nb_2O_5$ were investigated by XRD and SEM. Increasing the sintering temperature, the $2{\theta}$ value of BT(110) peak was shifted to the lower degree and intensity of the $Ba_6Ti_2Nb_8O_{30}$ (133) peak was increased. Increasing the addition of $Nb_2O_5$, the intensity of $BaTiNb_4O_{13}$ (201) peak was decreased and $Ba_6Ti_2Nb_8O_{30}$ (133) peak was increased. The grain size of the $BaTiO_3+Nb_2O_5$ ceramics sintered at $1500^{\circ}C$ were almost uniform.

• Proceedings of the KIEE Conference
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• 2002.11a
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• pp.94-96
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• 2002

The $0.97MgTiO_3-0.03SrTiO_3$ ceramics with $B_2O_3$(10wt%) were prepared by the conventional mixed oxide method. The structural properties were investigated with sintering temperature by XRD and SEM. According to the X-ray diffraction patterns of the $0.97MgTiO_3-0.03SrTiO_3$ ceramics with $B_2O_3$(10wt%), the ilmenite $MgTiO_3$ and perovskite $SrTiO_3$ structures were coexisted and secondary phase $MgTi_2O_5$ were appeared. Increasing the sintering temperature. the grain size was increased. In the case of $0.97MgTiO_3-0.03SrTiO_3$ ceramics with $B_2O_3$(10wt%), dielectric constant, quality factor and temperature coefficient of resonant frequency were $13.52{\sim}18.13,\;32750{\sim}51736GHz$, $-15.78{\sim}25.64ppm/^{\circ}C$, respectively.

• Journal of the Korean Chemical Society
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• v.44 no.3
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• pp.281-285
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• 2000

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.211-211
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• 2010

본 논문에서는 ZnO 박막을 휘어지기 쉬운 PES(polyethersulfone) 기판위에 PLD(pusled laser deposition)법을 사용하여 다양한 조건에서 성장시켰다. 성장된 ZnO 박막의 표면 형상과 광특성을 SEM과 PL을 사용하여 측정하였고, 레이저 밀도 0.3 J/$cm^2$, 기판 온도 $200^{\circ}C$에서 가장 좋은 광특성을 보였다.

• Proceedings of the Korean Society of Crop Science Conference
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• 2019.04a
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• pp.112-112
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• 2019